Share Email Print
cover

Proceedings Paper

AC magnetic-field-induced strain of single-crystal Ni-Mn-Ga
Author(s): Christopher P. Henry; Jorge Feuchtwanger; David Bono; Robert C. O'Handley; Samuel M. Allen
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

The dynamic field-induced strain response at 2Hz is reported for a ferromagnetic shape memory alloy (FSMA), Ni49.8Mn28.5Ga21.7. For the d31 actuation mode, longitudinal strain response was measured as a function of longitudinally applied bias stress and transverse applied field. Under a 1.5MPa compressive bias stress, dynamic strains of 2.6% were achieved at fields of 6 kOe. However, dynamic field-induced strain is largely blocked under a compressive bias stress of 4.2MPa. The 'coercive field' hysteresis in the field versus strain loops was observed to be as low as 100kA/m at 1.5MPa and increase linearly at greater stresses. Peak piezomagnetic d31 coefficients measured from these field versus strain loops approached 1.3 X 10-7 m/A. Dynamic stress versus strain loops were recorded for compressive bias stresses from 0 to 4.2MPa. Stiffnesses of approximately 40MPa in the active twinning stress range were recorded, and the stiffness approached 5 times the twinning stiffness beyond the twinning range. The mechanical loss measured in stress versus strain loops, when normalized to the output strain, resulted in a linear increase of 6.84 kJ/m3 per MPa bias stress. Current investigations are attempting to isolate the factors that contribute to the extraordinary behavior exhibited in these properties of the Ni-Mn-Ga system.

Paper Details

Date Published: 11 July 2002
PDF: 8 pages
Proc. SPIE 4699, Smart Structures and Materials 2002: Active Materials: Behavior and Mechanics, (11 July 2002); doi: 10.1117/12.474972
Show Author Affiliations
Christopher P. Henry, Massachusetts Institute of Technology (United States)
Jorge Feuchtwanger, Massachusetts Institute of Technology (United States)
David Bono, Massachusetts Institute of Technology (United States)
Robert C. O'Handley, Massachusetts Institute of Technology (United States)
Samuel M. Allen, Massachusetts Institute of Technology (United States)


Published in SPIE Proceedings Vol. 4699:
Smart Structures and Materials 2002: Active Materials: Behavior and Mechanics
Christopher S. Lynch, Editor(s)

© SPIE. Terms of Use
Back to Top